An organic electrophotographic photosensitive member (hereinafter, referred to as “electrophotographic photosensitive member”) containing an organic charge-generating substance (organic photoconductive substance) is known as an electrophotographic photosensitive member mounted on an electrophotographic apparatus. In an electrophotographic process, a variety of members such as a developer, a charging member, a cleaning blade, paper, and a transferring member (hereinafter, also referred to as “contact member or the like”) have contact with the surface of the electrophotographic photosensitive member. Therefore, the electrophotographic photosensitive member is required to reduce generation of image deterioration due to contact stress with such contact members or the like. In particular, in recent years, the electrophotographic photosensitive member is required to have a sustained effect of reducing the image deterioration due to contact stress with improvement of durability of the electrophotographic photosensitive member.
For sustained reduction of contact stress, Patent Literature 1 has proposed a method of forming a matrix-domain structure in the surface layer using a siloxane resin obtained by integrating a siloxane structure into a molecular chain. In particular, the literature shows that use of a polyester resin integrated with a specific siloxane structure can achieve an excellent balance between sustained reduction of contact stress and potential stability (suppression of variation) in repeated use of the electrophotographic photosensitive member.
On the other hand, there has been proposed a technology for adding a siloxane-modified resin having a siloxane structure in its molecular chain to a surface layer of an electrophotographic photosensitive member. Patent Literature 2 and Patent Literature 3 have each proposed an electrophotographic photosensitive member containing a polycarbonate resin integrated with a siloxane structure having a specific structure and a polyester resin integrated with a siloxane structure having a specific structure, and effects such as improvements in sliding property and durability of the surface of the photosensitive member.